This disclosure relates to polycarbonates having improved color and compositions comprising the polycarbonates. This disclosure further relates to methods for the manufacture of the polycarbonates and polycarbonate compositions, as well as articles comprising the polycarbonates and polycarbonate compositions.
Polycarbonates having good chemical and/or scratch resistance are useful in the manufacture of articles and components for a wide range of applications, from automobile components, to decorative articles, to housings for electronic appliances such as computers and cell phones. Excellent mechanical properties are also desired in a polycarbonate composition for use in these applications, as well as ease of manufacture.
Polycarbonate copolymers comprising repeat units in the polycarbonate derived from the monoaryl dihydroxy monomers hydroquinone (HQ) and methyl hydroquinone (MeHQ), and the diaryl dihydroxy monomer bisphenol A (BPA) can provide improved chemical and scratch resistance, as disclosed in US Pub. No. 2008/0033108 A1. Although polycarbonates are generally known for their optical clarity and their water-white color, during the synthesis of such polycarbonate copolymers, a reddish/yellow color can be formed. US Pub. No. 2008/0004379 A1 discloses that the color properties of polycarbonate terpolymers made using a melt polymerization process can be improved when using a phosphorus-containing compound, for example, phosphorous acid (H3PO3). However, it is desired that the color of polycarbonates incorporating both monoaryl and diaryl monomers be still further improved.